const xss = require('xss')
const { exec } = require('../db/mysql')

const getList = async (author, keyword) => {
    let sql = `select * from blogs where 1=1 `

    if (author) {
        sql += `and author='${author}'`
    }

    if (keyword) {
        sql += `and title like '%${keyword}%' `
    }

    sql += `order by createtime desc;`

    // 返回 promise
    return await exec(sql)
}

const getDetail = async (id) => {
    const sql = `select * from blogs where id='${id}'`
    const rows = await exec(sql)
    return rows[0]
}

const newBlog = async (blogData = {}) => {
    // blogData 是一个博客对象，包含 title content author属性

    const title = xss(blogData.title)
    const content = xss(blogData.content) 
    const author = blogData.author
    const createtime = Date.now() 

    const sql = `
        insert into blogs (title, content, author, createtime)
        values ('${title}', '${content}', '${author}', ${createtime});
    `
    const insertData = await exec(sql)

    return {
        id: insertData.insertId
    }
}

const updateBlog = async (id, blogData = {}) => {
    // blogData 是一个博客对象，包含 title content 属性

    // 更新时只需要更新blogData的 title content 属性

    const title = xss(blogData.title)
    const content = xss(blogData.content)

    const sql = `
        update blogs set title='${title}',content='${content}' where id=${id}
    `
    const updateData = await exec(sql)
    if (updateData.affectedRows > 0) {
        return true
    }
    
    return false
}

const deleteBlog = async (id, author) => {
    // id 就是要删除博客的id
    
    const sql = `
        delete from blogs where id=${id} and author='${author}'
    `
    
    const deleteData = await exec(sql)
    if (deleteData.affectedRows > 0) {
        return true
    }
    
    return false
}

module.exports = {
    getList,
    getDetail,
    newBlog,
    updateBlog,
    deleteBlog
}